1. Field of the Invention
This invention relates to wireless power and data communication, and more particularly to apparatus, subsea hub assemblies, and methods of providing power to charge power supplies for data gathering devices and to retrieve data from the data gathering devices.
2. Description of the Related Art
Industry members today are looking for more operating and maintenance data from their subsea systems. Also as a result of an increase in focus on employment and proper functioning of failsafe subsea operations, particularly on blowout preventer (BOP) systems, there is an increase in the requirement for, and utilization of, sensors to monitor primary and backup systems for early failure detection and prevent system failures from occurring.
Providing power to, and retrieving data from these additional sensors or other devices has been a challenge, particularly due to increased sensor needs. Although many subsea sensors can receive a direct electrical connection, various sensors, particularly newly added ones, must be powered by a stored energy device such as a battery. This is because, in some circumstances, there simply is not enough connection slots in the BOP receiver transmitter unit (RTU) for providing a wired electrical source to provide for powering these data gathering devices or for retrieving gathered data.
Adding to the problems, certain sensors, gauges, and other devices may need to be activated multiple times. Such usage, particularly when combined with the self-discharge of batteries, however, can result in a considerable depletion of the batteries' power. Further, wireless data transmission, which can consume considerable amount of power, further complicates power management of the devices.
The options available under normal circumstances is replacement of batteries at fixed intervals or providing batteries that are oversized to enable them to perform over the entire period of deployment. Changing out the batteries, however, generally requires the tasking of a remote operated vehicle (ROV). Particularly in deep water, a considerable amount of time and money can be spent performing something as simple as changing even a relatively small number of batteries. Utilizing oversized batteries can be expensive and can cause significant issues with respect to their placement within the crowded stack space.